[SOLVED] Help! Many algebra problems :(

Hey, I'm a high school student and recently came back to school after a long period of absence (appendicitis ) and my teacher gave me a 2-page packet with a bunch of problems from the chapters I missed, and he gave me all the notes to learn how to do them on my own. I am struggling very much and these problems are due tomorrow! I would greatly appreciate if anyone could help me out, even if you just solve 1 or 2.

1. Find the slope of the line between the points (-10, -4) and (-3, -3)

2. Write the equation in slope-intercept form for the line that contains the point (-2,7) and is parallel to y = 3x – 4

3. Write an equation in slope-intercept form for the line that contains the point (8,-1) and is perpendicular to the graph y=4x-3

4. Solve for x in the proportion 6x-3/9 = 3x/8

5. Use the table provided to (a) Write the linear regression equation and (b) tell how many students were enrolled in AP statistics for the 4th year.
Year 1 2 3 5 6 7
Enrollment 33 30 43 47 58 65

6. Solve for x in the following equation 2/5x + 6/5 = x-3

7. Solve and graph the solution(s) for the following inequalities 2x – 3 > 1 or 3x+7 < 1

10. Tell whether or not the following equation represents a function. Then give the domain, range, and zeros. f(x) = 9 – x^2

A function is a relation (a set of ordered pairs (x,f(x)) ) such that there is only one f(x) for each x.

A simple way to test if you have a function is to graph f(x). If you can draw ANY vertical line through the graph that cuts the graph in more than one place then f(x) is not a function.

The graph of f(x) = 9 - x^2 shows that it is indeed a function. (See attachment below.)

There are no values of x such that f(x) is not defined. (Typically such a value of x would make the denominator of the function 0. We don't have any fractions here.) So the domain of the function is all real numbers: .

The range is a bit trickier. Note that the function has a maximum value: f(max) = 9. There is no lower bound to the function, so the range of the function is .

Zeros of a function are values of x such that f(x) = 0. So we need to solve

12. Find the inverse of the following function. Then use the composition of functions to prove that your equations are inverses of each other. f ( x ) = x-1 / 3

I'm assuming this is:

A function and its inverse have a kind of symmetry: calling y = f(x), the graph of f(x) and it's inverse are reflections over the line y = x. This means that, in order to find the inverse of the function y = f(x) what we need to do is switch the x and y in the equation: x = f(y). Once we solve this for y we have our inverse function.

So:

Switch x and y:

Now solve for y:

So the inverse function is . (Typically we use the notation for the inverse function.)

Now we need to show that these functions are inverses of each other. If this is true then we should be able to show that
and

There are several ways to solve systems of equations. This one is called the "substitution method." It's occasionally more trouble that the other methods, but it has the advantage of being one of the more systematic methods.

What we want to do is solve one of the equations for one of the unknown variables. We then insert this value into the second equation. This provides us with an equation in a single unknown. We can solve this and use this value in either of the original equations to find the value of the other variable.

For example:

As it happens, the top equation is already solved for s. I will use this value of s in the second equation:

This is an equation in a single unknown, t, which we can solve:

We now use this value of t in either of the original equations to get a value for s: